Matthew Gale designed a jacket that functions as a sleeping aid for when you're on public transit, called Excubo. He came up with the concept after learning that people sleep on public transportation when their bodies are held in a rigid state rather than loose and bouncing around.
Couple this idea with Timothy Dubitsky's Hood.e that integrates headphones into the hood and you can drown out the ambient noise that comes with public transportation by lulling yourself to sleep with your music. All of this, of course, would be discretely integrated into the garment so it becomes your second skin while helping you catch your Z's.